钠应用于电光源上是由于（ ）
A．高压钠灯发出的黄光射程远，透雾力强
B．钠很软
C．钠是一种强还原剂
D．钠燃烧发出黄色火焰
答案：A
题目分析：所有的灯都是光源，而高压钠灯发出的黄光射程远，透雾力强，对道路平面的照明度比高压水银灯高几倍，故将钠应用于电光源上，答案选A。
点评：该题是识记性知识的考查，难度不大，记住即可，有利于调动学生的学习兴趣，激发学生的学习积极性。常见物质的用途应注意知识的积累和总结。
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| Upon receiving the Nobel Peace Prize, Mother Teresa said, "What can you do to 1 world peace? Go home and love your 2 and love your friends. Love them without measure". A 3 story tells of a woman who finally decided to ask her boss for a raise in salary. All day she felt 4 . Late in the afternoon she gathered 5 to see her employer. To her 6 the boss agreed to a raise. The woman 7 her home that evening to a beautiful table set with their best dishes. Her husband had come home early and prepared a festive meal. She 8 if he somehow knew that she would not get 9 . She found him in the kitchen and 10 him the good news. They hugged and kissed, then sat down to the 11 meal. Next to her plate the woman found a beautifully lettered note. It read, " 12 , darling! I knew you'd get the raise! These things will tell you how much I 13 you." Following the supper, her husband went into the kitchen to 14 . She noticed that a second 15 had fallen from his pocket. Picking it off the floor, she read, "Don't worry about not getting the 16 ! You deserve (应得) it anyway! These things will tell you how much I love you." Someone has said that the measure of love is when you love without 17 . What this man feels for his wife is 18 acceptance and love, 19 she succeeds or fails. His love 20 her victories and soothes her wounds. He stands with her, no matter what life throws in their direction. | |||
| ( )1.A. urge ( )2.A. parents ( )3.A. sad ( )4.A. nervous ( )5.A. energy ( )6.A. worry ( )7.A. reached ( )8.A. considered ( )9.A. turned down ( )10.A. declared ( )11.A. optimistic ( )12.A. Good luck ( )13.A. respect ( )14.A. bring up ( )15.A. letter ( )16.A. award ( )17.A. measure ( )18.A. instant ( )19.A. either ( )20.A. celebrates | B. promote B. children B. pleasant B. excited B. strength B. disappointment B. got B. argued B. turned off B. told B. wonderful B. Cheers B. admire B. clean up B. notice B. promotion B. intention B. appropriate B. whether B. admits | C. construct C. wife C. frightening C. desperate C. power C. delight C. arrived C. wondered C. turned over C. informed C. successful C. Congratulations C. envy C. make up C. note C. raise C. discussion C. necessary C. when C. encourages | D. approach D. family D. moving D. dangerous D. courage D. horror D. returned D. thought D. turned out D. proved D. convenient D. Help yourself D. love D. dress up D. poster D. reward D. doubt D. total D. no matter D. believes in |